<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<link rel="stylesheet" href="bootstrap-4.6.2-dist/css/bootstrap.min.css">
<link rel="stylesheet" href="bootstrap-4.6.2-dist/js/bootstrap.min.js">
<body>
    <!-- Default dropup button -->
<div class="btn-group dropup">
    <button type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-expanded="false">
      Dropup
    </button>
    <div class="dropdown-menu">
      <!-- Dropdown menu links -->
    </div>
  </div>
  
  <!-- Split dropup button -->
  <div class="btn-group dropup">
    <button type="button" class="btn btn-secondary">
      Split dropup
    </button>
    <button type="button" class="btn btn-secondary dropdown-toggle dropdown-toggle-split" data-toggle="dropdown" aria-expanded="false">
      <span class="sr-only">Toggle Dropdown</span>
    </button>
    <div class="dropdown-menu">
      <!-- Dropdown menu links -->
    </div>
  </div>
</body>
</html>